<!doctype html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport"
        content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Login</title>
</head>

<body>
    <div style="text-align: center;">
        <h1>登录</h1>
        ⽤户：<input id="username">
        <br>
        密码：<input id="password" type="password">
        <br>
        <input type="button" value=" 提交 " onclick="mysub()" style="margin-top: 20px;margin-left: 50px;">
    </div>
    <script src="./js/jquery-3.3.1.min.js"></script>
    <script>
        function mysub() {
            var username = $("#username");
            var password = $("#password");
            if(jQuery.trim(username.val())==""){
                alert("请先输入用户名！");
                username.focus(); // 光标重制到此元素
                return;
            }
            if(jQuery.trim(password.val())==""){
                alert("请先输入密码！");
                password.focus(); // 光标重制到此元素
                return;
            }
            $.ajax({
                type: "post",
                url: "/login",
                contentType: "application/json",
                data: JSON.stringify({ "username": username.val(),
                    "password": password.val()}),
                success: function (res) {
                    alert(JSON.stringify(res));
                }
            })
        }

    </script>
</body>

</html>